Evaluation of Horizontal Subgrade Reaction Modulus for Integral Abutment Based on Changes in Buffering Zone Stiffness

Abstract

The buffering zone, which can control the stiffness of the backfill material, is applied at the integral abutment (IA) to reduce the horizontal earth pressure on the abutment and decrease the residual settlement at the transition zone. Numerical analyses are performed to evaluate the horizontal subgrade reaction modulus based on the stiffness change in the buffering zone. A 1 m section from the back of the abutment is set as the buffering zone, and materials such as sandy soil, gravel, and cement-mixed gravel are applied differently. By implementing the buffering zone, the passive and active coefficients of the horizontal subgrade reaction decrease by 28% and 31% at the height of 6.8 m. respectively. Hence, the possibility of adjusting the horizontal subgrade reaction of the IA by changing the stiffness of the buffering zone is confirmed.